Integral Dual Functionality Cleaning Pads

ABSTRACT

A cleaning pad has a facing layer joined to a backsheet, and an absorbent core disposed between the facing layer and backsheet. The facing layer is an integral sheet having a first region comprising a plurality of apertures, and a second region comprising a plurality of raised protrusions. The two different regions provide dual functionalities of absorbing (or distributing) liquid, such as a cleaner, and scrubbing, respectively.

FIELD OF THE INVENTION

The present invention relates to floor cleaning pads and more particularly to floor cleaning pads having a textured surface for cleaning a target surface.

BACKGROUND OF THE INVENTION

Cleaning pads are well known in the art. Such pads are used for cleaning a target surface, such as a floor or other hard surface. Floors commonly cleaned with a pad include linoleum, tile, wood, etc.

For convenience, the cleaning pad may be removably attached to a cleaning implement. The cleaning implement may have an elongate handle for grasping by the user. The handle may be typically attached to a head by universal joint. Alternatively the handle and head may be in fixed relationship, as often occurs with a loop handle. The cleaning pad may be removably attached to the bottom of the head, for movement relative to the target surface during cleaning. Attachment may be accomplished using one or more grippers. Suitable grippers may be made according to commonly assigned U.S. Pat. Nos. 6,305,046; 6,484,346; and/or 6,651,290. Alternatively the pad may be removably adhesively attached or attached using hook and loop fasteners. Suitable cleaning implements include the Swiffer® Sweeper, Swiffer® WetJet® and Swiffer® SweeperVac® sold by the instant assignee.

Such cleaning pads may also be used with water, or in other cleaning solution to solubilize debris on the floor. The pads may be wetted and/or cleaning fluid may be distributed onto the floor from a reservoir. One suitable implement for cleaning with a pad and distributing cleaning fluid from a replaceable reservoir includes the Swiffer® WetJet® implement sold by the instant assignee. Such an implement may be made according to commonly assigned U.S. Pat. No. 6,386,392. Alternatively, a suitable pre-wetted cleaning pad includes the Swiffer® Sweeper Wet Cloths sold by the instant assignee and made according to commonly assigned U.S. Pat. No. 6,716,805.

The cleaning pads retain the dual functionality of transmitting cleaning solution to/from the pad and scrubbing debris or stains which may be difficult to remove from the floor. However, this dual functionality is not optimally met by a single surface of the cleaning pad. A surface suitable for transmitting cleaning fluid therethrough is not optimized for scrubbing debris and vice versa.

One solution to this problem is to provide two different materials, each having a surface optimized for the task of transmitting liquids therethrough or the task of scrubbing debris. However, this solution raises even more problems. Having two materials for the sheet increases inventory and assembly costs. Assembly may not properly occur, leading to scrap. Even if assembly is proper, the extra step of assembling the two materials as part of the production of the cleaning pad may slow the production, again increasing cost.

Thus, the efforts to make a better cleaning pad continue. One such effort is found in the cleaning pad of the present invention.

SUMMARY OF THE INVENTION

The invention comprise a cleaning pad for attachment to the head of a cleaning implement. The pad comprises a backsheet and a facing sheet joined in face-to-face relationship with an absorbent core therebetween. The facing sheet comprises an integral sheet having a first region with apertures therethrough, and a second region having a plurality of protrusions extending outwardly therefrom and away from the core.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a cleaning pad according to the present invention with the cleaning surface facing upwardly, shown partially in cutaway.

FIG. 2 is a vertical sectional view of the pad of FIG. 1, taken along line 2-2.

FIG. 3 is a schematic perspective view of an apparatus suitable for making the sheet of the present invention.

FIG. 4 is a line profile plot representing an instantaneous sectional view of the facing sheet of the cleaning pad of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, a cleaning pad 20 according to the present invention may comprise a plurality of layers joined in face-to-face relationship to define an XY plane and Z-direction orthogonal thereto. The layers may comprise a facing layer 21 according to the present invention, an absorbent core 24, and a backsheet 22. Optionally, the backsheet 22 may have adhesive attachments on the outwardly facing surface.

The center of the cleaning pad 20 is defined at the junction of a centrally-disposed longitudinal axis L and a centrally disposed transverse axis T. Longitudinal axis L and transverse axis T define a two-dimensional plane of the cleaning pad, which, in the embodiment shown is associated with the machine direction (MD) and cross machine direction (CD), respectively as are commonly known in the art.

The backsheet 22 may be any liquid impervious sheet flexible, yet capable of imparting sufficient strength to the pad. One suitable backsheet 22 may be made of a laminate of spunbond/meltblown/spunbond fibers, as is known in the art.

The optional core 24 may be any layer capable of holding fluid and optionally delivering fluid. Fluid may be transmitted from the surface being cleaned, through the facing layer 21 to the core 24 or may be transmitted from the core 24 to the surface to be cleaned. The core 24 may further comprise absorbent gelling material as is known in the art, to increase its capacity. A suitable pad 20 may be made with a core 24 generally according to the teachings of commonly assigned U.S. Pat. Nos. 5,960,508; 6,003,191; 6,101,661 and/or 6,766,552. If desired, an optional secondary topsheet 27 may be included to improve fluid transmission and strength of the facing sheet 21.

The facing layer has a first region 12 comprising a plurality of apertures, and a second region 14 comprising a plurality of raised, out-of-plane deformations that can be protrusions 31. The two regions 12, 14 are differentiated by the kind of topographical features disposed in each. The facing sheet 21 is the component of the cleaning pad 20 which contacts and cleans the target surface, such as a floor, in use. The facing sheet 21 is integral. By integral it is meant the facing sheet 21, or other desired component of the cleaning pad 20, is formed from a single raw material and is not made by joining two separate components together.

In particular, apertures 28 are disposed in, and may extend through, first region(s) 12 of the facing layer 21 may be sufficiently large (e.g., at least about 1 to 2 mm² each) to permit relatively viscous fluids, to flow through the facing layer 21 and into absorbent core 24 and less than 8 to 9 mm² to minimize leakage. First region(s) 12, may be disposed generally centrally to cleaning pad 20, and the second region 14 may be disposed outwardly of the first region 12, or vice versa with the second region 14 centrally disposed and the first region 12 outboard thereof. In another embodiment, the first region 12 and second region 14 may overlap, to provide a region having both apertures 28 and out-of-plane protrusions 31.

The embodiment illustrated in FIG. 1 has the structural feature that protrusions 31 extend from the peripheral area of the cleaning pad in the Z-direction, while the apertures 28 are centrally disposed. This arrangement provides the benefit that applied force, compressively transmitted by the user through the handle of the cleaning implement tends to be centrally applied to the head of the cleaning implement. By having Z-direction deformations disposed away from the handle in the XY plane, the compressive force is more uniformly distributed in the XY plane. This relatively more uniform force distribution is believed to result in a more uniform compressive stress across the head of the cleaning implement when used in conjunction with the cleaning pad 20 of FIG. 1. This improved stress distribution is believed, in turn, to yield improved cleaning of the target surface and more complete usage of the cleaning pad 20.

Protrusions 31 may be disposed in second region 14 of facing layer 21. In general, by “out-of-plane” is meant extending in the “Z”-direction, as indicated by FIG. 2. In FIG. 2 protrusions 31 are shown in exaggerated proportion, although there are not believed to be particular dimensional limitations. The only design considerations with respect to the dimensions of protrusions 31 are those related to the desired cleaning task. It may be that for particular facing layers 21 the height (Z-direction) of protrusions 31 can be uniform; in other embodiments the height can vary, such as by increasing with greater distance from longitudinal centerline L. The protrusions 31 may extend about 0.5 to about 4 millimeter, and about 1 to about 3 millimeters in the Z-direction. In one embodiment, protrusions 31 are disposed generally outboard of first region 12, as shown in FIG. 1.

As shown in FIGS. 1 and 2, protrusions 31 can comprise raised ridges of a pre-defined length that is much shorter than the length of the cleaning pad, measured along the longitudinal centerline, for example. In one embodiment as shown in FIG. 1, protrusions 31 are disposed in a regular pattern of protrusions 31 that form a pattern of diamond-shapes, each diamond shape being comprised of a plurality of protrusions 31. In this manner, the protrusions 31 may contribute to scrubbing capability. In general, the individual protrusions 31 can have a length, measured along their longitudinal orientation, of between 1% and 50% of the length of the cleaning pad, measured along the longitudinal axis. The individual protrusions 31 may have a spacing in the XY plane such that there is not an unbroken path from any portion of the first region 12 to either of the longitudinal side edges of cleaning pad 20.

The facing layer 21 can comprise nonwoven materials as are known in the art for facing layers on disposable absorbent articles and cleaning pads 20. Absorbent core 24 and backsheet 22 may likewise comprise absorbent materials, and film materials, respectively, as are well known in the art. An optional secondary facing layer can be used as a distribution layer to distribute fluid in the XY directions.

The dual cleaning benefit of the present invention is in part due to apertures 28 and protrusions 31 that form discrete regions of facing layer 21. Apertures 28 provide for relatively unimpeded fluid flow of cleaning fluid and even viscous fluid. Raised, protrusions 31 may act as a plurality of individual fluid barriers, each effective in retarding any free fluid flow that may have a tendency to run off the facing layer 21 when cleaning pad 20 is used, without becoming a total block of fluid distribution to outboard portions of the cleaning pad 20. In addition protrusions 31 may function as resilient textured wipers, to help clean debris from the target surface.

As shown in FIG. 2, apertures 28 permit fluid communication through the facing layer 21. Typically, inner surface of the facing layer 21 is in contact with absorbent core 24 to allow efficient fluid flow into the core 24. Apertures 28, and discrete raised, protrusions 31 may also add elastic extensibility to facing layer 21.

Although all the raised, protrusions 31 are shown as being aligned longitudinally in the MD, the raised, protrusions 31 could be oriented in any desired configuration. Other patterns of apertures 28 and protrusions 31 are within the scope of the invention, including, for example, a discrete region in the center of the cleaning pad 20 having apertures, the discrete region not extending to any of the peripheral edges. Also, apertures 28 and protrusions 31 could be in a striped pattern with the stripes generally transversely, longitudinally, diagonally oriented or aligned in a combination thereof. The first region 12 may comprise from about 30 to about 90 percent, or about 40 to about 80 percent of the width of the cleaning pad 20.

FIG. 3 shows an apparatus for making facing layer 21 of the present invention that is suitable for use with cleaning pad 20. Facing layer 21 may formed from a generally planar, two dimensional nonwoven precursor web 200 on apparatus 100, the apparatus may be oriented for continuous web processing with respect to a machine direction (MD) and a cross machine direction (CD) as is commonly known in the art of nonwoven webs. Precursor web 200 has formed therein in predetermined regions a plurality of melt-weakened portions 115 prior to entering nip 116. Melt-weakened portions 115 are formed in predetermined regions of web 200 by thermal point calendaring in the predetermined regions, the predetermined regions corresponding to first region(s) 12 of facing layer 21, that is, the region where apertures 28 are ultimately desired. Each melt-weakened portion 115 of the predetermined region may be generally elongated and/or oriented in the MD. Upon stretching in the CD in the portion of the apparatus 100 corresponding to the region 113, the melt-weakened portions 115 rupture to form apertures 28. The melt-weakened portions 115 may be limited to the central region of web 200, that is, corresponding to the central first region 12 of cleaning pad 20 in FIG. 1.

The apparatus 100 may comprise a pair of rolls 102 and 104, each rotating about parallel axes A, and is similar in many respects to the apparatuses described in commonly assigned U.S. Pat. Nos. 5,916,661; 5,628,097 and 5,518,801 issued to Chappell et al. and U.S. 2004/0127875 published in the name of Hammons et al. By combining both into one apparatus to form both apertures 28 and protrusions 31 in one facing layer 21, the cleaning pad 20 of the present invention provides for significant cleaning and fluid handling benefits over prior art cleaning pads. Further, such facing layer 21 provides these benefits in with an integral facing layer 21, further providing for convenient and inexpensive manufacture.

The apparatus 100 shown in FIG. 3 may comprise a roll 102 having a plurality of circumferentially-extending ridges 106 separated by grooves 108, as disclosed in the above-mentioned patents and as well known in the art of “ring-rolling.” A second, intermeshing roll 104 comprises a first region 113 having essentially matching roll 102 and having ridges 106 separated by grooves 108. The intermeshing ridges 106 and grooves 108 of rolls 102 and 104 incrementally stretch precursor web 200 to form apertures 28 as disclosed in U.S. Pat. Nos. 5,916,661 and 5,628,097. Of course, precursor web 200 has melt-weakened regions 115 formed therein prior to precursor web 200 entering the nip 116 of apparatus 100.

In addition to region 113, roll 104 may have two regions 111 comprising ridges with teeth 110, the toothed ridges separated by grooves 112. Ridges 106 of roll 102 intermesh with the grooves 112 of roll 104 to form the protrusions 31 of second region(s) 14. A pitch of about 0.7 to 13 millimeters, and particularly about 1.5 millimeters may be utilized for the second region 14. A pitch of about 0.7 to 13 millimeters, and particularly about 2.5 millimeters may be utilized for the first region 12. The rolls 102, 103 may have an engagement of about 0.5 to 26 millimeters, independent of pitch.

Facing layer 21 has a first region 12 defined on both sides of facing layer 21 by having a plurality of spaced apart apertures 28. A second region 14 is defined by a plurality of spaced-apart protrusions 31 which may be integral extensions of the fibers of the precursor web 200.

One advantage of the apparatus 100 described above is that the facing layer 21 can be produced in-line with other production equipment on a manufacturing line for producing such articles. For example, an apparatus 100 such as disclosed above, can be made as a unit operation for an existing manufacturing line. As a unit operation, such apparatus 100 can be modular, so that it can be easily changed out. When used as part of a manufacturing line for cleaning pads 20, the constituent rolls 102, 104 need not be much wider than the product itself, thereby providing for relatively easy installation and removal. Various patterns of first regions 12 and second regions 14 can therefore be implemented with a minimum interruption.

FIG. 4 shows a line profile plot of an exemplary cleaning pad 20 according to the present invention. In this embodiment, first region 12 is disposed generally central with respect to the cleaning pad 20. The second region 14 is disposed outboard of first region 12, in a region extending from first region 12 to an area adjacent longitudinal edges of the cleaning pad 20.

The protrusions 31 in the second regions 14 function to scrub or loosen debris from the target surface. The apertures 28 in first region 12 then function to absorb liquid cleaner deposited on the target surface and retain debris on the cleaning pad 20. The pad 20 and debris can then be discarded.

The dimensions and other values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such value is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.”

Every document cited herein, including any cross referenced or related patent or application, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention. 

1. A cleaning pad for attachment to the head of a cleaning implement, said pad comprising: a backsheet and a facing sheet joined in face-to-face relationship with an absorbent core therebetween, said facing sheet being an integral sheet having a first region having apertures therethrough, and a second region having a plurality of protrusions extending outwardly therefrom and away from said core.
 2. A cleaning pad according to claim 1 wherein said cleaning pad is generally rectangularly shaped having two spaced longer edges and two spaced apart shorter edges, each of said backsheet and said facing sheet having two spaced apart longer edges and two spaced apart shorter edges, said longer edges of said backsheet extending outwardly beyond said longer edges of said facing sheet.
 3. A cleaning pad according to claim 2 having a border between said first region and said second region, wherein said border between said first region and said contiguous second regions is substantially straight.
 4. A cleaning pad according to claim 3, having said first region intermediate two second regions, wherein one of each said second regions is juxtaposed with each said longer edge.
 5. A cleaning pad according to claim 4 having a width between said longer edges, and said first region comprises from 30 to 90 percent of said width.
 6. A cleaning pad according to claim 5, wherein said first region and said second regions are contiguous.
 7. A cleaning pad according to claim 5, wherein said first region has apertures with an open area ranging from about 1 to about 9 square millimeters per aperture.
 8. A cleaning pad according to claim 7, wherein said second region has protrusions extending outwardly about 0.5 to about 4 millimeters.
 9. A cleaning pad according to claim 1 wherein said first region and said second region overlap.
 10. A cleaning pad according to claim 9 wherein said first region substantially circumscribes said second region.
 11. A cleaning pad according to claim 1 wherein said first region and said second region are separated by a visually discernable region free of said plurality of protrusions and free of said apertures.
 12. A cleaning pad according to claim 11 wherein said second region substantially circumscribes said first region.
 13. A cleaning pad according to claim 1 removably attached to a cleaning implement, said implement comprising a handle and a head attached thereto, wherein said backsheet of said cleaning pad is attached to said head.
 14. A cleaning pad according to claim 13 which is premoistened. 